Folding measuring rule

ABSTRACT

IN A FOLDING MEASURING RULE EACH PAIR OF ADJACENT LIMBS IS PIVOTALLY HINGED BY A RIVET. EACH SUCH HINGE INCLUDES A RESILIENT LOCKING ELEMENT EXTENDING BETWEEN THE TWO LIMBS AND WITH AT LEAST ONE PROJECTION OUT OF THE PLANE OF THE RULE. ONE OF THE LIMBS OF THE PAIR HAS AT LEAST ONE DEPRESSION INTO WHICH SAID PROJECTION IS ENGAGEABLE WHEN THE LIMBS ARE IN FULL OPEN OR CLOSED POSITION, THE LOCKING ELEMENT BEING RESILIENTLY DISPLACEABLE AWAY FROM THE LIMB WITH DEPRESSION DURING PIVOTING OF THE LIMBS.

Nov. 30, 1971 A. QUENOT 3,623,230

FOLDING MEASURING RULE Filed Nov. 24, 1969 United States Patent3,623,230 FOLDING MEASURING RULE Andre Quenot, Besancon, France,assignor to Manufacture Quenot Mabo, Zone lndustrielle, Trepillot,Besancon, France Filed Nov. 24, 1969, Ser. No. 879,029 Claims priority,application France, Dec. 2, 1968, 176,221 Int. Cl. B431 7/06 US. Cl.33-118 7 Claims ABSTRACT OF THE DISCLOSURE In a folding measuring ruleeach pair of adjacent limbs is pivotally hinged by a rivet. Each suchhinge includes a resilient locking element extending between the twolimbs and with at least one projection out of the plane of the rule. Oneof the limbs of the pair has at least one depression into which saidprojection is engageable when the limbs are in full open or closedposition, the locking element being resiliently displaceable away fromthe limb with depressions during pivoting of the limbs.

This invention relates to folding measuring rules. Rules are known ofthe type which are made of a number of limbs which fold one upon anotherat hinges formed by rivets and are made of a synthetic plasticsmaterial. These rules may include means for ensuring the maintenance ofthe folded or unfolded position of two adjacent limbs, namely twometallic springs mounted on the ends of the limbs in the same manner ason folding rules made of wood or of duralumin of a conventional type.

It has also already been proposed to form directly by injection mouldingthe reliefs and bosses allowing the engagement of two adjacent limbs inopen or closed position. This technique, which consists in forming onthe limbs in a synthetic plastics material, the springs of plasticsmaterial already used on the duralumin rules, ensures a better frictionat the level of the articulation whilst being of a lower cost tomanufacture. However, the elasticity of such a hinge is practically niland rules thus made would in practice not be useable. To remedy thisdifficulty, it is already known to provide the hinge of a metallicspring by a piano wire passing the head of the rivet joining twoadjacent branches. It is thus possible to lightly swing aside the twolimbs one from another at the moment of their rotation.

The first type of folding rule with metallic springs inserted isrelatively expensive and its hinges do not show any progress withrespect to those of rules of the conventional type.

In the case of hinges with bosses made directly by injection, thefriction of the two limbs one on the other leads fairly rapidly, despitethe use of a piano wire spring, to the gradual wearing of the surfacespresent whilst the chemical alternation of the plastics material leadsto the progressive disappearance of the intrinsic elasticity of the saidsurfaces. At the end of a certain time, only the elasticity of themetallic spring is then effective, but the relative displacement of thetwo limbs along the hinge rivet then leads to the wearing of the rivetor the portion of the limb co-operating with the rivet. The amount ofplay at the hinge then becomes excessive in all directions and canresult in the total deterioration of the articulation. According to thenature of the synthetic material forming the limbs of the folding rule,this effect can be further increased by the relatively increasedfriction of two surfaces of identical nature rubbing one against theother.

It is therefore an object of the invention to provide a foldingmeasuring rule which may be made of synthetic material, wherein thevarious disadvantages described above are overcome and which has aconsiderably increased life of its hinges.

According to the invention there is provided a folding measuring rulewherein each pair of adjacent limbs is pivotally hinged by a rivet,wherein each such hinge in- I cludes a locking element made of resilientmaterial which extends between the two limbs and has at least oneprojection out of the plane of the rule, and one of the limbs of thepair has at least one depression into which said projection isengageable when the limbs are in fully open or closed positions, thelocking element being resiliently displaceable away from the limb havingthe depressions during pivoting the limbs.

The invention will be further described with reference to a preferredembodiment thereof as shown in the accompanying drawings, wherein:

FIG. 1 represents a view from above of a hinge and portions of theadjacent limbs of a rule according to the invention which is in the openposition.

FIG. 2 is a section along line 11-11 of FIG. 1;

FIG. 3 is a view from below of the upper limb, the lower limb beingremoved;

FIG. 4 is a transverse section of the rule and hinge, passing throughthe rivet on line IVIV of FIG. 2;

FIGS. 5 and 6 are views from above and below respectively of the upperlimb without its hinge mechanism.

Referring to FIGS. 1 and 2, the folding rule according to the inventioncomprises limbs such as 1 and 2 made of a synthetic material, forexample, covered or reinforced by some fibre (such as glass). The end ofthe upper limb 1 is provided, at its lower face, with a recessed area 3of rectangular shape. Four holes 4 pass through the limb 1 at thecorners of the recessed area 3, and said recessed area receives alocking bar 5 made of synthetic selflubricating material, for example ofthe type sold under the trade mark Delrin.

The locking bar 5 which is of rectangular shape has at its four corners,four circular projections (bosses or teats) 6 which can engage in theholes 4. The locking bar also has a central annular projection 7extending both above and below the bar and projecting into pivotingholes of corresponding dimensions which are formed in the limbs 1 and 2.A rivet 8, which may be metallic, passes through the projection 7through a central hole 9 formed therein, and effects the connectionbetween the two limbs 1 and 2 at the hinge.

The locking bar 5 also preferably has a certain intrinsic elasticitywhich permits its two extremities situated at the level of theprojection 6 to merge above the lower face of the limb 1 so as to formreliefs such as that shown at 10 in FIG. 2. These reliefs penetrate intoa corresponding depression 11, of rectangular form, formed in the upperface of the limb 2. Looking together of the two limbs is thus effectedby means of this penetration of the bar 5 into the hole 11.

During the relative rotation of the limbs 1 and 2 with respect to oneanother, the bar 5 can be temporarily displaced within the rectangularhollow 3 which allows the two branches to pivot one over the otherpractically without deformation of the limbs at the level of theiroverlapping avoids the limbs made of synthetic material being subjectedto permanent deformation since the limbs are not subjected to anyconstraint.

Furthermore, the self-lubricating character of the synthetic materialforming the locking bar, which avoids the friction of the limbs of thesame type one on another, reduces the friction of the bar with the lowerlimb which thus reduces the risk of deterioration and wearing of thehinge.

It is thus possible to increase the firmness of the resilient barassembly by including on the upper part of the limb 1, and held by therivet *8, an H-shaped metallic spring 12 (FIG. 4). The limbs 13 of thisspring 12 are cambered downwardly so that the ends of the limbs engageover the projections 6 so as to ensure a precise positioning of theadjacent limbs in open or closed position. The H-spring 12 is preferablyarranged inside a correspondingly shaped depression (-FIG. 5). Thespring 12 thus does not increase the thickness of the hinge and can alsocontribute to ensure a further rigidity to the limb 1 at the region ofthe hinge.

It is also possible to arrange, under the lower face of the limb 2, andin a hollow of corresponding form to that of the depression 14, a spring15 (FIG. 4) identical to the spring 12. This spring 15, which is alsopreviously cambered, further allows the general elasticity of the hingeto be increased. It is to be noted that the springs 12 and 15 do notextend to the edges of the rule and this allows the continuation as faras the end of each limb of the centimetric or other gradation of theselimbs.

The invention is not limited to the particular form described. Thus theshape of the engagement element such as the locking bar can be alteredand the reliefs which are formed thereon can have any configurationprovided that they co-operate with complimentary reliefs or depressionsof the adjacent limb. The elasticity of the engagement elements can beof the same nature as that of the bar or of the springs described oreven of a combination of the two. The limbs of the rule can have acertain looseness along the rivet or can have onl a very short playalong this rivet according to different embodiments.

What is claimed is:

1. In a hinge for connecting two sections of a folding measuring rule,an improvement comprising, in combination, first and second sections ofa folding measuring rule, each said section having a recessed area in anend portion thereof, a rivet pivotally joining said end portions of saidsections wherein said recessed areas are disposed in a face-to-facerelation, and wherein said rivet is disposed centrally of said recessedarea of said second section, a resilient locking member disposed withinsaid recessed area of said first section and extending longitudinally ofsaid first section, said locking member having a free end and having anopposing end fixed with respect to said first section, and means forresiliently urging said free end of said locking member into saidrecessed area of said second section to impede pivotal relative movementof said sections when said sections are aligned longitudinally, whereinsaid relative pivotal movement causes defiection of said locking memberout of said second recess, and whereby said first and second sectionsare resiliently held in place when aligned longitudinally and arepivotal with respect to each other in a deflection-free manner.

2. A hinge for connecting two sections of a folding measudirlig rule asset forth in claim 1, in which said first section as a hole passingtherethrough in communication with said recessed area of said firstsection and in alignment with said free end of said locking member, andin which said means for urging said free end of said locking member intosaid second recessed area comprises a projecting portion connected tothe free end of said locking member and extending into said hole, andfirst spring means attached to said first section and extending oversaid hole to contact said projecting portion to resiliently impedemovement of said projecting portion further into said hole.

3. A hinge for connecting two sections of a folding measuring rule asset forth in claim 2, further comprising second spring means disposedbetween a head of said rivet and said second section for resilientlyurging said first and second sections into close contact.

4. In a hinge for connecting two sections of a folding measuring rule,an improvement comprising, in combination, first and second sections ofa folding rule, each said section having a rectangular recessed area inan end portion thereof, a rivet pivotally joining said end portions ofsaid sections wherein said recessed areas are disposed in a face-to-facerelation, and wherein said rivet is disposed centrally of both saidrecessed areas, a rectangular, plateshaped, resilient locking memberdisposed within said recessed area of said first section, said lockingmember having a transverse sleeve fixed centrally thereof and extendingthrough said first and second sections and receiving said rivettherethrough, and means for resiliently urging the longitudinally remoteportions of said locking member into said recessed area of said secondsection to impede pivotal movement when said sections are alignedlongitudinally.

5. A hinge for connecting two sections of a folding measuring rule, asset forth in claim 4, in which said first section has four holestherethrough at the corners of its said recessed area, and in which saidmeans for urging said locking members into said second recessed areacomprises four projections connected one each to the respective cornersof said locking member for extending into said holes, and first springmeans connected to said first section for covering said holes to engagesaid projections and resiliently urge said locking member toward saidsecond section.

6. A hinge for connecting two sections of a folding measuring rule, asset forth in claim 5, further comprising second spring means disposedbetween a head of said rivet and said second section for resilientlyurging said first and second sections into close contact.

7. A hinge for connecting two sections of a folding measuring rule, asset forth in claim 5, in which said first spring means comprises anH-shaped spring having an interconnecting member and four legs extendingtherefrom, wherein said interconnecting member receives said rivettherethrough for being held in place, and wherein said four legs coversaid four holes.

References Cited UNITED STATES PATENTS 986,772 3/1911 Simpson 33-120FOREIGN PATENTS 734,150 5/1966 Canada 33-105 18,845 1901 Great Britain33-405 45,509 8/1908 Switzerland 33-119 HA-RRY N. HAROIAN, PrimaryExaminer US. Cl. X.R. 33.105

